The name comes from the thicker club shape at the end of the abdomen. Notice the narrow yellow stripes on the top of the black abdomen, wide spaced blue eye, dark thorax with yellow strips.

Waxmyrtle Trail - Oregon Dunes National Recreation Area - July 19, 2015 - - - The two lower photos show copulating male and female. The male grabs the female at the back of her neck with the end of his abdomen, she wraps her legs around his abdomen and cures the end of her abdomen up to his thorax for contact.